I just got my shiny new Dellbuntu, and since GnuPG integration is much better on Ubuntu than it is on Windows I thought I'd make a concerted effort to actually use it this time. What I was wondering though is how I should set up my keys: not the technical details, but which and how many keys I should set up.

Essentially, should I just have a single keypair which expires every so often (I'm planning to have them expire once a year, at the end of the year - incidentally should I set 31st December or 1st January for this?), or should I have a non-expiring 'master key', which I use only for signing the regular key whenever I create a new one?